9. Soldering asymmetry: Inadequate flow due to poor flux or heating. 10. Loose connection: Movement of wire or lead leading to poor conduction. 11. Tip sharpening: Exposed tip due to insufficient flux or incorrect iron angle. 12. Bridging: Connection between adjacent wires causing short circuit due to excessive solder. 13. Pinholes: Visible holes indicating weak spots caused by excessive gap or poor penetration. 14. Bubbles: Bulging solder concealing cavities, caused by gaps or prolonged soldering. 15. Upturned copper foil: Peeling off due to excessive heat and time. 16. Stripping: Separation of solder joints from the pad due to poor metal plating.